About This PhD Project

Project Description

Each year, about 12,500 people in Scotland have a stroke. Survivors have a cumulative risk of recurrent stroke, myocardial infarction (MI), or vascular death of about 30% at five years. Recurrent strokes comprise about a quarter of all strokes, and thirty-day case fatality is almost double that of index strokes, with more disability and increased costs.

Timely introduction of antiplatelets, statins, antihypertensives, or appropriate anticoagulants are a major part of stroke secondary prevention guidelines and could result in a cumulative relative risk reduction of vascular events of 80%(1). Despite this, evidence-based secondary prevention therapies (for example, statins, antithrombotics, antihypertensives, anticoagulation where appropriate) are not given to all at risk patients. The reasons for this are not clear although these are likely to include frailty and safety concerns (particularly around anticoagulants).

The purpose of this studentship is to use routinely collected data to describe prescribing patterns in stroke patients, identify the characteristics of patients not given or discontinued from secondary prevention, and compare outcomes with those who are appropriately treated.

We have created a novel population based linkage of stroke registry, hospital episode, death registry and a national prescription dispensing database. This includes the Scottish Stroke Care Audit (SSCA) cohort of patients admitted to hospital or attending outpatient clinics between 2010 and 2015 (40,000+ patients). This has been linked with Scottish Morbidity Records (SMR01) and General Registry Office (GRO) mortality datasets to capture subsequent events, and also linked to the national Prescribing Information System (PIS), which includes data on all NHS prescriptions dispensed in the community in Scotland. This novel dataset includes information on the stroke event, treatment started/recommended at discharge, all dispensed medication at monthly time points, outcomes (recurrent admissions (ICD10 code), death) and comorbidity score calculated from SMR/dispensing data. Multivariable survival analysis (eg Cox proportional hazards model) will be used to estimate treatment effect on the outcomes. Further multilevel modelling including potentially time series analysis, immortal time bias, will take into account medication changes over time.

The successful applicant will look at the rates of recurrent stroke, vascular events and death up to four years after the index stroke event. The PhD student will use this data to answer the following questions:

(1) In a population-based cohort of stroke/TIA survivors, how many were taking antiplatelets, anticoagulants, lipids and blood pressure lowering medication prior to, and after their index event?

(2) To what extent do age, gender, social deprivation, living circumstances, stroke severity/subtype, independence in activities of daily living (ADL) and comorbidities influence prescribing? Once started, are treatments continued or stopped; what factors are associated with this?

(3) How does initial prescription, continuation and cessation of appropriate secondary prevention (including anticoagulation for atrial fibrillation (AF)) impact on survival and further events over follow-up?

(4) Which components of a secondary prevention ‘bundle’ are most important for reduction of mortality/subsequent vascular events?

(6) How many patients remain on medications known to increase risk of stroke, eg NSAIDs, OCP, antipsychotics?

They will use statistical modelling to estimate the impact of these on subsequent vascular events or death, taking into consideration potential biases including stroke severity, discharge destination, comorbidities, time to initial treatment or discontinuation of treatment. This work will provide evidence to underpin recommendations for implementation of secondary prevention guidelines at practice/hospital level, which will impact directly on patient outcomes in Scotland and beyond.

The PhD student will learn skills in handling large datasets, epidemiology and statistical analysis methods. The supervisors have a track record in stroke research (2,3) and will provide appropriate support. There is close working with the Chronic Disease Research Group, the Grampian Safe Haven (DASH) and nationally with the Farr Institute and Scottish Stroke Care Audit. This is an exciting opportunity to contribute to informing best evidence based health care for patients with stroke.

Application:

Please select ’Degree of Doctor of Philosophy in Medical Sciences (Medicine)’ from the list of programme options in the University of Aberdeen’s online postgraduate applicant portal to ensure that your application is passed to the correct school for processing. Then manually enter the name of the supervisor(s), project title and funder (Elphinstone) in the space provided.

Funding Notes

This project is part of a competition funded by the Elphinstone Scholarship Scheme. Successful applicants will be awarded full tuition fees (UK/EU/International) for the duration of a three year PhD programme. Please note that this award does not include a stipend.

This award is available to high-achieving students. Candidates should have (or expect to achieve) a minimum of a First Class Honours degree in a relevant subject. Applicants with a minimum of a 2.1 Honours degree may be considered provided they have a Distinction at Masters level.